This paper introduces an optimal scheduling framework for the Earth observation tasks of multiple agile satellites based on nonlinear modeling of attitude change time for the task transition. An attitude control module using a quaternion feedback constructs the database storing the time to complete the attitude change maneuver for a given initial and final attitude pair. A mixed-integer linear programming

This paper presents a practical method to compute the four-dimensional flight trajectories of aircraft in the presence of winds. The proposed method consisted of numerically integrating the aircraft equations of motion over different segments that compose a typical commercial flight profile. For this purpose, the aircraft vertical trajectory was divided into seven typical flight segments: unrestricted

Journal of Aerospace Information Systems, Ahead of Print.

Journal of Aerospace Information Systems, Ahead of Print.

To achieve system resilience, one can leverage high-level design features (e.g., redundancies and fail-safes), adjust operational profiles (e.g., load or trajectory), and use appropriate contingency management (e.g., emergency procedures) to mitigate potential hazards. For example, in the design of a novel drone, one would optimize the rotor and battery pack architectures (design), flight-plan (operations)

Journal of Aerospace Information Systems, Ahead of Print.

Journal of Aerospace Information Systems, Ahead of Print.

This work proposes a fast algorithm for generating obstacle-free and wind-efficient flight paths at a constant above-ground-level altitude in urban environments because a fast flight path planning algorithm is an essential function or service needed for enabling small unmanned aerial vehicle (sUAV) to operate in urban environments within Class G airspace. The proposed method first converts the 3D path

This work addresses the iterated nonstationary assistant selection problem, in which over the course of repeated interactions on a mission, an autonomous robot experiencing a fault must select a single human from among a group of assistants to restore it to operation. The assistants in our problem have a level of performance that changes as a function of their experience solving the problem. Our approach

Rosetta was a European Space Agency (ESA) cornerstone mission that launched in March 2004, exited hibernation in January 2014, entered orbit around the comet 67P/Churyumov-Gerasimenko in August 2014, and escorted the comet through September 2016, executing the most detailed study of a comet ever undertaken by humankind. The Rosetta Orbiter had 11 scientific instruments (4 remote sensing) and the Philae

Location privacy of aircraft has recently gained attention as air traffic management was modernized using novel surveillance technologies. Business aviation circles and various military and government entities voiced serious concerns about automated and ubiquitous tracking. Consequently, some flight authorities have started addressing these operational privacy issues with novel programs. A first analysis

Unmanned aerial systems (UASs) are continuing to proliferate. Quantitative risk assessment for UAS operations, both a priori and during the operation, are necessary for governing authorities and insurance companies to understand the risks and properly approve operations and assign insurance premiums, respectively. In this paper, the problem of UAS risk analysis and decision making is treated through

A policy for six-degree-of-freedom docking maneuvers with rotating targets is developed through reinforcement learning and implemented as a feedback control law. Potential clients for satellite servicing and orbital debris objects are often rotating around a constant axis within their respective Earth orbits. In the context of such missions, reinforcement learning provides an appealing framework for

The stabilized approach is important to avoid aircraft accidents during landing. Although there are many possible factors that can lead to an unstable approach, actions can be taken to mitigate the risk if the reason for unstable approaches is identified properly. However, because unstable approaches are rarely observed, it is difficult to identify the relevant reasons by analyzing unstable approaches

Two image-based sensing methods are merged to mimic human vision in support of airborne detect-and-avoid and counter–unmanned aircraft systems applications. In the proposed sensing system architecture, a peripheral vision camera (with a fisheye lens) provides a large field of view, whereas a central vision camera (with a perspective lens) provides high-resolution imagery of a specific target. Beyond

There is a growing interest among scientists to coordinate diverse and temporally responsive measurements from multiple space and ground-based observatories in order to obtain greater insights into transient scientific events than would otherwise be possible. Many transient scientific events of interest occur randomly and the scientific value of follow-up observations decays with time. As a result

Onboard far-field aircraft detection is needed for safe non-cooperative traffic mitigation in autonomous small unmanned aerial system (sUAS) operations. Machine vision systems, based on standard optics and visible light detectors, possess the ideal size, weight, and power (SWaP) requirements for sUAS. This work presents the design and analysis of a novel aircraft detection and tracking pipeline based

An autonomous guidance and flight control system was integrated and flight tested on a Black Hawk helicopter as part of an effort to provide all weather capability for U.S. Army fleet rotorcraft. The guidance and flight-control system components were previously flight tested on a full-authority helicopter, and were adapted to fly on the partial-authority test helicopter of this paper. The main autonomy

This work proposes a set of complementary practices to agile methodologies, aiming at adapting them to the development of critical aerospace embedded systems by distributed teams. To identify the main gaps in this context, two approaches are used. The first one confronts the main activities required by aerospace standards for the development of critical embedded systems with a set of compiled agile

This paper presents a computer architecture with the ability to respond to radiation-induced faults. The architecture presented advances the state-of-the-art by implementing a redundant multiprocessor system on a commercial-off-the-shelf field programmable gate array. The system, called RadPC, can respond to radiation-induced faults and undergo repairs as necessary. A reliability analysis is conducted

Delay tolerant networks (DTNs) offer a set of standardized protocols to enable Internet-like connectivity across the solar system. Unlike other protocols such as the Transmission Control Protocol (TCP) and the Internet Protocol (IP), DTN protocols are robust to end-to-end connection disruptions and long delays. Although the behavior of DTN core protocols is well understood, management of DTNs is still

Active attitude control systems using a novel six-layer electromagnetic embedded printed air coil for small satellites with various dimensions are presented in this paper. The proposed designs are optimized in terms of available area, generated torque, power dissipation, and generated magnetic dipole moment. The designed printed air coils are the best choice for small satellites’ attitude stabilization

This paper describes three approaches to enabling a severely computationally limited embedded scheduler to consider a small number of alternative activities based on resource availability. This paper considers the case where the scheduler is so computationally limited that it cannot backtrack search. The first two approaches precompile resource checks (called guards) that only enable selection of a

Tracking space objects is important for managing space traffic and predicting collisions, but is difficult in part due to data association and orbit model uncertainty. Expectation–maximization (EM) is a commonly used tracking method that has not been widely considered for tracking space objects. The technique consists of iteratively computing data association probabilities with a set of current element

Increased interest in body–machine interfaces necessitates understanding how to train users to use nontraditional inputs. In this study, a control task driven by subject-activated surface electromyography was developed as a testbed to observe the effects of automated training methodologies on the development of performance, workload, and trust. Forty-eight subjects learned to use a surface-electromyography-based

Scheduling the coverage of a celestial body by scientific instruments onboard multiple spacecraft under observational constraints is central in a significant number of current and future missions for the exploration of the solar system. This paper describes the components and algorithms of a software system used to study early-phase mission design or to schedule daily operations of currently in-flight

Deep reinforcement learning was used to train an agent within the framework of a Markov decision process (MDP) to pursue a target, while avoiding a defender, for the target–attacker–defender (TAD) differential game of pursuit and evasion. The aim of this work was to explore the games where the previous attacking guidance methods found in literature failed to capture the target. The reward function

Studied here is the problem of multiple unmanned aerial vehicles flying in formation in an environment containing many obstacles and threats. Two schemes are proposed for avoiding obstacles: formation dissolution and formation change. The improved interfered fluid dynamical system approach is used to guide the unmanned aerial vehicles to their destination safely, and an artificial potential field is

Terrain relative navigation can improve the precision of a spacecraft’s state estimate by providing supplementary measurements to correct for drift in an inertial measurement unit. This paper presents a crater detector, LunaNet, that uses a convolutional neural network (CNN) and image processing methods to detect craters from camera imagery taken by a spacecraft’s onboard camera. These detections are

This paper describes the development of a framework that integrates engineering software and agile tools based on ontologies and business rules. The aim of this integration is to help project managers specify their own rules of integration between development software and agile tools. This integration circumvents the limitations of on-the-shelf plugins that perform a very basic integration that not

This paper investigates different strategies for end-to-end flight software development that support having both desktop and embedded environments while minimizing the existing gap between them, in order to facilitate reiteration back and forth of the flight application. For desktop prototyping, the use of Python as a user-facing language wrapping C/C++ algorithm source code is considered. The Basilisk

It was found that a newly developed portable collision alert radar receives reflections from the ground while flying. In this paper a method is developed that uses range and Doppler information from these reflections. This information is used to compute height and velocity information relative to the terrain, something which is not possible with existing hardware. The method was tested on a local flight

A method for the fast computation of spacecraft force and torque due to solar radiation pressure (SRP) is presented. A faceted model is employed that tracks which elements of a time-varying geometry are exposed to the sunlight, but sunlight reflections are not modeled. The method uses the highly parallel execution capabilities of commodity graphics processing unit (GPU) and the Open Graphics Library

Tracking an object in a noisy environment is difficult, especially when unknown parameters affect the object’s behavior. In the case of a high-speed ballistic object, its trajectory is affected by changes in atmospheric conditions as well as various parameters of the object itself. To filter these latent factors of the dynamics model, this paper proposes a black-box expectation–maximization algorithm

Pilots use situational awareness (SA) to make appropriate aeronautical decisions. Autonomous vehicles will not have a human pilot (or operator) in the loop when off-nominal conditions present themselves, and will rely on sensors to build SA on their environment to make sound aeronautical decisions. As their sensors degrade, it is hypothesized that a point exists where the SA those decisions are based

For satellite interactions missions such as autonomous docking, the key to successful completion of these missions is to autonomously and accurately detect targets’ information. The missions with high precision requirement need not only to obtain the categories and location of target satellite components but also to obtain the high-level information such as the corner point. In this paper, a satellite

This paper presents a system to command and control a team of fixed-wing unmanned aerial vehicles (UAVs) to sense dynamic wildfire boundaries. UAV team task and trajectory planning strategies enable the team to rapidly find, rally around, and map the wildfire boundaries. A novel boundary estimation algorithm generates two-dimensional concave polygonal estimates of multiple dynamic boundaries given

Journal of Aerospace Information Systems, Ahead of Print.

The growing numbers, complexity, and data return of space missions are driving a need for automated fault detection and diagnosis. Traditional fault monitoring techniques possess limited ability to diagnose anomalies, requiring operators to investigate extensive amounts of telemetry to isolate root causes. An important hurdle to automating fault diagnosis for complex subsystems such as attitude determination

This paper investigates the effect of employing different display design principles for human–machine interaction in helicopters. Two obstacle avoidance support displays are evaluated during low-altitude forward flight. A baseline head-up display is complemented either by a conventional advisory display or a constraint-based display inspired by ecological interface design. The latter design philosophy

This paper addresses a path planning problem for unmanned aerial vehicles with correcting position errors through correction-point navigation, which requires a rapid response when determining the flight path. A two-layer nested iterative hybrid algorithm based on Q learning is proposed to achieve multiobjective optimization by minimizing path lengths and correction times while reducing the complexity

The goal of system identification is to learn about underlying physics dynamics behind the time-series data. To model the probabilistic and nonparametric dynamics, Gaussian process (GP) has been widely used; GP can estimate the uncertainty of prediction. Traditional GP state-space models, however, are based on the Gaussian transition model, and thus they often have difficulty in describing more complex

Advancements in aircraft controller design, paired with increasingly flexible aircraft concepts, create the need for the development of novel (smart) adaptive sensing methods suitable for aeroelastic state estimation. A potentially universal and noninvasive approach is visual tracking. However, many tracking methods require manual selection of initial marker locations at the start of a tracking sequence

This work examines the problem of fusing human operator observations with probabilistic information extracted by an automated data fusion system, in the context of dynamic multitarget track characterization for large-scale surveillance. This soft data fusion problem is challenging because human operator observation errors are difficult to calibrate a priori and in general exhibit subtle conditional

Motivated by the success of deep learning in recent years, prediction-based methods are used to compress satellite telemetry data. In this paper, two-stage lossless compression methods for telemetry data are demonstrated. In the first stage, different approaches of long short-term memory (LSTM) based on one-to-one, many-to-one, and many-to-many network architectures are presented. The framework of

Journal of Aerospace Information Systems, Volume 18, Issue 1, Page 1-2, January 2021.

In this paper, an online flight envelope protection system is developed and implemented on impaired aircraft with structural damage. The whole protection system is designed to be a closed loop of several subsystems, including system identification, damage classification, flight-envelope prediction, and fault-tolerant control. Based on the information given by damage classification, the flight envelopes

Journal of Aerospace Information Systems, Ahead of Print.

This paper presents a method developed at the Laboratory of Applied Research in Actives Controls, Avionics, and AeroServoElasticity for calculating takeoff and departure trajectories of a Cessna Citation X business aircraft. The method consisted of integrating the aircraft equations of motion for each segment corresponding to a typical takeoff and departure profile. For this purpose, the aircraft trajectory

The last 15 years have seen a large uptick in the use of unmanned aircraft. However, the current safety of flight clearances for unmanned aircraft requires a qualified operator who can make decisions and ultimately bear the responsibly for the safe operations of the vehicle. The future of aviation is unmanned, and ultimately autonomous. Yet, a clear path for certifying an autonomous vehicle to make

In modern air transportation, the direct share is the ratio of direct passengers to total passengers on a directional origin and destination (O&D) pair. The forecasting of direct share time series on the O&D level, as part of the detailed demand forecasting, plays a fundamental role in air transportation planning and development. An accurate forecasting of the O&D direct share time series can benefit

The arrival sequencing and scheduling problem have been formulated in the urban air mobility (UAM) context for homogeneous and mixed fleets of electric vertical takeoff and landing (EVTOL) aircraft (winged/wingless) expected to land on a vertiport. In this paper, a novel UAM airspace design concept has been proposed to separate arrival air traffic of wingless EVTOL aircraft from winged EVTOL aircraft

Autonomous operation of unmanned aerial vehicles (UAVs) requires development of technologies that allow for safer flight control and response to various flight anomalies. Software for autonomous control should allow the UAV to detect and avoid potential hazards, as well as respond to critical failures midflight without input from a human operator. This paper develops a ground impact and hazard mitigation

Computational fluid dynamics through the solution of the Navier–Stokes equations with turbulence models has become commonplace. However, simply solving these equations is not sufficient to be able to perform efficient design optimization with a flow solver in the loop. This paper discusses the recommendations for developing a flow solver that is suitable for efficient aerodynamic and multidisciplinary

Automated aerial refueling (AAR) provides unique challenges for computer vision systems. Aerial refueling maneuvers require high-precision low-variance pose estimates. The performance of two stereoscopic (stereo) vision systems is quantified in ground tests specially designed to mimic AAR. In this experiment, three-dimensional (3-D) pose-estimation errors of 6 cm on a target 30 m from the current vision

This paper presents a new method for predicting unimpeded taxi time based on the airport node–link model through statistical analysis of the airport surface detection equipment surveillance data. The proposed method can predict taxi-out and taxi-in times for departure and arrival flights, respectively, by calculating the link travel times on a node–link model of the airport surface movement. The prediction

With the aim to benefit vertical guidance in performance-based navigation using the multiconstellation global navigation satellite systems, this research addresses the integrity of the detection and exclusion of faulty global navigation satellite system measurements with the parameterized quadratic programming (PQP) method proposed in prior research. In particular, the PQP method is integrated with

The continuous dynamics of unmanned aerial vehicles (UAVs) are generally modeled as a set of differential equations. Traditionally, these continuous dynamics of UAVs are analyzed using paper-and-pencil proof and computer-based testing or simulations to study the performance, stability, and various other control characteristics of the aircraft flying in the air. However, these techniques suffer from

This paper describes a concept and a prototype for sharing flight information using blockchain technology. Providing all stakeholders access to complete, consistent, and up-to-date information about each flight facilitates efficient aviation operations. Existing flight information exchange methods are limited; the concept of a “flight object” that provides a complete solution for all stakeholders has

This paper describes the development of a computational framework for aerodynamic simulations based on the unsteady vortex lattice method under the object-oriented programming paradigm. The effort aims to fulfill the fluid-dynamics portion of the fluid–structure interaction problem in the multiphysics field. The construction and implementation of an object-oriented model is introduced along with its